CPX-351 is a liposomal formulation of cytarabine and daunorubicin approved for the treatment of adults with newly diagnosed, therapy-related acute myeloid leukemia (t-AML) or AML with myelodysplasia-related changes (MRC-AML). We retrospectively analyzed the efficacy and safety of CPX-351 in a real-world setting in 103 patients from 12 French centers, including the evaluation of molecular abnormalities at baseline and minimal residual disease (MRD) in responding patients, compared with a historical data set from Bordeaux-Toulouse DATAML registry. A favorable safety profile was observed, with a low frequency of alopecia (11%) and gastrointestinal toxicity (50%). The overall response rate after induction was 59%, and MRD <10−3 was achieved in 57% of complete response (CR)/CR with incomplete hematological recovery (CRi) patients. Only the presence of mutated TP53 (P = .02) or PTPN11 (P = .004) predicted lower response in multivariate analysis. Interestingly, high-risk molecular prognosis subgroups defined by 2017 European LeukemiaNet risk stratification, including ASXL1 and RUNX1 mutations, were not associated with a significantly lower response rate using CPX-351. With a median follow-up of 8.6 months, median overall survival (OS) was 16.1 months. Thirty-six patients underwent allogeneic stem cell transplantation with a significantly longer median OS compared with nontransplanted patients (P < .001). In multivariate analyses, only spliceosome mutations were associated with better OS (P = .04). In comparison with intensive chemotherapy, there was no difference in OS for patients <60 years. These data confirm the efficacy and safety of CPX-351 in high-risk AML (t-AML and MRC-AML) in a real-life setting. CPX-351 is a treatment of choice for patients aged ≥60 years.

FLT3-mutated acute myeloid leukemia accounts for around 30% of acute myeloid leukemia (AML). The mutation carried a poor prognosis until the rise of tyrosine kinase inhibitors (TKIs). New potent and specific inhibitors have successfully altered the course of the disease, increasing the complete response rate and the survival of patients with FLT3-mutated AML. The aim of this article is to review all the current knowledge on these game-changing drugs as well as the unsolved issues raised by their use for fit and unfit FLT3-mutated AML patients. To this end, we analyzed the results of phase I, II, III clinical trials evaluating FLT3-TKI both in the first-line, relapse monotherapy or in combination referenced in the PubMed, the American Society of Hematology, the European Hematology Association, and the Clinicaltrials.gov databases, as well as basic science reports on TKI resistance from the same databases. The review follows a chronological presentation of the different trials that allowed the development of first- and second-generation TKI and ends with a review of the current lines of evidence on leukemic blasts resistance mechanisms that allow them to escape TKI.

Introduction CPX-351 is a liposomal formulation of cytarabine and daunorubicin packaged at a 5:1 molar ratio. This drug has recently been approved by FDA and EMEA for patients with therapy-related acute myeloid leukemia (t-AML) or AML with myelodysplasia-related changes (MRC-AML). The primary objective of this study was to analyze the efficacy of CPX-351 in a real-life setting, evaluating the impact of mutations on response and minimal residual disease (MRD) in responding patients. Methods We retrospectively collected data from patients treated by CPX-351 in eleven centers in France. Clinical, biological and treatment information were available for all patients. NGS (19 genes or more) was performed in 67 patients (84%) at diagnosis. Overall response rate (ORR) was defined by complete remission (CR) and CR with incomplete haematological recovery (CRi). Among the patients in CR or CRi, 25 (56%) had MRD evaluation assessed by NGS or flow cytometry. Overall survival (OS) was calculated from the date of AML diagnosis to the date of death or last follow-up. All statistical analyses were performed using SPSS v.22 software (IBM SPSS Statistics). Results Between April 2018 and July 2019, 80 patients treated with CPX-351 were included in this study. Sex ratio M/F was 43/37 and median age was 66 years old (range 20-83). AML subtypes were MRC-AML (61%) including AML with prior myelodysplastic syndrome (MDS-AML) (33%), prior chronic myelomonocytic leukemia (CMML-AML) (7%), or t-AML (29%). Sixteen patients (20%) had received prior treatment by hypomethylating agents (HMA), at the time of MDS diagnosis, before AML evolution. According to ELN 2017 classification, genetic risk was favorable, intermediate and adverse in 1 (1%), 31 (38%) and 47 (58%), respectively. 36% and 28% patients had complex and monosomal karyotypes, respectively. Assessed by NGS the most frequent mutated gene were : RUNX1 (n=17, 25%), TP53 (n=15, 22%), ASXL1 (n=14, 21%), TET2 (n=13, 19%), DNMT3A (n=11, 16%), srsf2 (n=9, 13%), FLT3-ITD (n=8, 12%), CBL (n=7, 10%), WT1 (n=7, 10%), and EZH2 (n=7, 10%). According to a genetic ontogeny-based classifier (Lindsley et al., Blood 2015), 23 patients (34%), 29 (43%), 15 (22%) had de novo/pan-AML, secondary type mutations AML, and TP53 mutated AML, respectively. Only 4 patients discontinuing treatment due to prolonged haematological toxicity. Early death rate was 5% and 8.75% through day 30 and day 60, respectively. Median time to neutrophil recovery (>0,5 G/L) and platelet recovery (>20G/L) after induction was 29 days (range 19-78) and 28 days (range 12-77), respectively. Seventy-five patients (95%) had at least one grade 3 or more AEs, including 69 (86%) febrile neutropenia. We observed gastrointestinal toxicity 32 patients (40%) (nausea/vomiting (30%/11%), mucositis (15%)) including 4% with grade 3 or more and alopecia in only 12%. ORR was 45/80 (56%) after induction 1 including 53% CR and 3% CRi. ORR increased to 58% after induction 2. Among the 45 CR/CRi patients, 25 were evaluable for MRD at the time of the 1st consolidation. 72% had MRD below 10-3 (64% below 10-4). Prior treatment by HMA and presence of monosomal karyotype were identified as factors predicting a lower rate of CR/CRi (P=0.001 and P=0.002, respectively). Lindsley's classifier predicted significantly a better chemosensitivity in de novo/pan-AML mutations (P= 0.037). Poor molecular prognosis subgroups defined by 2017 ELN risk stratification (n = 53) as TP53, ASXL1, RUNX1 and EVI1 mutations were not associated with a lower response rate with CPX-351 (Table 1). Twenty-one (26%) patients underwent an allogeneic haematopoietic stem cell transplant (HSCT) with an improved median OS compared to non-transplanted patients (non reached vs 8 months, P= 0.004). With a median follow up of 8.5 months, median OS was not reached. Survival analysis in subgroups will be available for the ASH meeting. Conclusion These data confirmed the efficacy and safety of CPX-351 in poor risk AML (t-AML and MRC-AML). The high rate of CR with low MRD compares favorably with previous report using 7+3 in elderly unfavorable AML (Sylvie D. Freeman et al., JCO 2013) and may explain the favorable outcome observed in patients after HSCT. Moreover, CPX-351 erases the poor prognosis associated with unfavorable mutations defined in 2017 ELN risk stratification. Lindsley's classifier was the best prognostic scoring system in patients treated by CPX-351. Disclosures Bertoli: Daiichi Sankyo: Consultancy; Astellas: Consultancy, Honoraria; Sanofi: Honoraria; Jazz Pharmaceuticals: Honoraria. Peterlin:Jazz Pharma: Consultancy; AbbVie Inc: Consultancy; Astellas: Consultancy; Daiichi-Sankyo: Consultancy. Chevallier:Incyte: Consultancy, Honoraria; Daiichi Sankyo: Honoraria; Jazz Pharmaceuticals: Honoraria. Thomas:INCYTE: Honoraria; DAICHI: Honoraria; PFIZER: Honoraria; ABBVIE: Honoraria. Mohty:Jazz Pharmaceuticals: Honoraria, Research Funding. Pigneux:Daichi: Honoraria; Abbvie: Honoraria; Jazz: Honoraria; Astellas: Honoraria; Roche: Honoraria; Pfizer: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria; Amgen: Honoraria; Novartis: Honoraria. Recher:Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Macrogenics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sunesis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ades:Amgen: Research Funding; Helsinn Healthcare: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Silence Therapeutics: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. Cluzeau:Abbvie: Consultancy; Jazz Pharma: Consultancy; Menarini: Consultancy.

Purpose: To provide insights into the diagnosis and management of therapy-related myeloid neoplasms (t-MN) following PARP inhibitors (PARPi). Experimental Design: In a French cancer center, we identified and described the profiles of 13 t-MN diagnosed among 37 ovarian cancer (OC) patients referred to hematology consultation for cytopenia under PARPi. Next, we described these 13 t-MN post PARPi among 37 t-MN post OC according to PARPi exposure. Finally, we described 69 t-MN post PARPi in a national cohort. Results: From 2016 to 2021, cumulative incidence of t-MN was 3.5% (13/373) among OC patients treated with PARPi. At time of hematological consultation, patients with t-MN had a longer PARPi exposure (9 months vs. 3, p= 0.01), lower platelet count (74 vs. 173 G/L, p=0.0005), and more cytopenias (2 vs. 1, p=0.0005). Compared to t-MN not exposed to PARPi, t-MN-PARPi patients had more BRCA1/2 germline mutation (61.5% vs. 0% p=0.03) but similar OS. In the national cohort, most t-MN post PARPi had a complex karyotype (61%) associated with a high rate of TP53 mutation (71%). Median OS was 9.6 months (IQR, 4-14.6). In multivariate analysis, a longer time between end of PARPi and t-MN (HR 1.046, p=0.02), olaparib compared to others PARPi (HR 5.82, p=0.003) and AML (HR 2.485, p=0.01) were associated with shorter OS. Conclusions: In a large series, we described a high incidence of t-MN post PARPi associated with unfavorable cytogenetic and molecular abnormalities leading to poor OS. Early detection is crucial, particularly in cases of delayed cytopenia.

PC. Baseline characteristics between the arms included lower baseline ANC (<0.5 x 10 9 /L, 42.4% vs. 21.1%); greater TP53 abnormalities (11.9% vs 5.3%); and increased proportion of prior MDS (11.0% vs 5.3%) in the selinexor group. The median OS for selinexor versus PC was 94 days versus 170 days, (HR = 1.18 [95% CI 0.79-1.75]; P = 0.4221). CR/CRi was observed in 12% of patients on selinexor, and 4% of the PC-treated patients. The most common TEAEs in the selinexor arm included nausea (59.1%), decreased appetite (55.7%), fatigue (46.1%), diarrhea (40.0%), thrombocytopenia (33.9%), vomiting and pyrexia (27.8%). In PC-treated patients, the most common TEAEs included febrile neutropenia (35.6%), constipation (33.3%), fatigue (28.9%), pyrexia (28.9%), anemia (26.7%), thrombocytopenia (24.4%), and dyspnea (22.2%). The most common SAEs in the selinexor and PC groups were febrile neutropenia and pneumonia. Febrile neutropenia occurred at a lower rate in the selinexor group (17.4%) than in the PC group (35.6%). The incidence of TEAE leading to death was identical in each arm (20%). Summary/Conclusion: The primary endpoint was not met and selinexor treatment did not show a significant difference in median OS compared with treatment of PC in this patient population. There was no increased TEAE of death between the 2 arms. There were several factors that may have led to this result. First, the trial was designed to allow DNMTI-experienced patients, but not necessarily DNMTi-refractory patients, so the survival estimates in the PC were subsequently influenced by responses to SOC DNMTi therapy in patients who were not refractory to DNMTi therapy. Second, the imbalances in the presence ofTP53, depth of neutropenia at enrollment, and transformed MDS indicate a higher risk population in the selinexor arm. Therefore, the results of this study support further investigation of selinexor in carefully selected populations of AML patients.

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BACKGROUND Post myeloproliferative neoplasms (MPN) acute myeloid leukemia (AML) occurs respectively in 1.5%, 7.0% and 11% of patients with essential thrombocytosis (ET), polycythemia vera (PV) and primary myelofibrosis (PMF). This subgroup of AML has very poor prognosis and are often excluded from clinical trials. Therefore, only few cohorts including molecular data are available. MATERIAL AND METHODS We retrospectively collected data from 111 patients treated in four centers in France for post MPN-AML. Clinical, molecular and treatment information was available for all patients at AML and MPN stages. DNA was extracted from samples at diagnosis of MPN chronic phase, at diagnosis of AML phase and after induction treatment. JAK2-V617F mutations were identified by qPCR (Ipsogen® MutaQuant kit, Qiagen, Germany), MPL-W515L/K mutations were identified by PCR (Ipsogen® MutaScreen kit, Qiagen, Germany) and CALR mutations were identified by conventional sequencing (Applied Biosystems, 3500Genetic Analyzer). NGS on 36 genes using Ampliseq librairy and Ion Proton sequencing (Thermofisher, Waltham, MA, USA) were performed in 96/111 patients. Overall response rate (ORR) was defined by complete remission (CR), CR with incomplete hematologic recovery (CRi), partial remission (PR) and stable disease (SD). Overall survival (OS) was calculated from the date of AML diagnosis to the date of death or last follow-up. All statistical analyses were performed using SPSS v.22 software (IBM SPSS Statistics). RESULTS 111 patients treated for post MPN-AML were retrospectively included in this study. Sex ratio M/F was 54%/46%. Median age at AML diagnosis was 66 years (28-89, range). Cytogenetic categories were favorable, intermediate and adverse in 2 (2%), 51 (46%) and 47 (42%) patients, respectively. 25/111 (23%) patients had a monosomal karyotype (MK). Median number of additional mutations excluding from JAK2/MPL/CALR mutations was 2 (0-6, range). The most frequent additional mutations were TP53 (23%), ASXL1 (17%), TET2 (13%), SRSF2 (10%), DNMT3A (8%), SF3B1 (8%) and RUNX1 (8%). Only 2 patients were mutated for NPM1 and 2 and 4 patients were FLT3-ITD and FLT3-TKD, respectively. Prior MPN were PV, ET and PMF in 20%, 34% and 46% of patients, respectively. First line treatment was intensive chemotherapy (IC) for 61 (55%) patients, hypomethylating agents (HMA) for 10 (9%) or other treatments including best supportive care, cytoreduction for the other ones. 24/111 (22%) underwent to ASCT. ORR was 54% (with 30/71 (42%) in CR/CRi) in patients treated by IC or HMA. We did not identify factors predicting a higher rate of CR/CRi. OS was 12 months [6-18] and was not influenced by transplant, cytogenetic categories or by the type and allele frequencies of JAK2/CALR/MPL mutations. OS was significantly longer in the group treated with HMA as compared to IC (10 versus 46 months, respectively, p=0.006); in patients with prior PV as compared to ET or MF (26 months [0-57] versus 10 months [7-13] versus 10 months [4-16] respectively, p=0.07) and in patients with presence of additional mutations other than JAK2/CALR/MPL (5 months [0-12] versus 46 months [32-60] in 38 patients without mutation versus 58 patients with presence of at least one mutation, respectively, p=0.04). By multivariate analysis, only presence of additional mutations was predictive for OS with a hazard ratio (HR) = 0.42 [0.18-0.97] (p=0.04). Finally, we followed the VAFs of JAK2 in seven patients before and after IC. We observed in 2 patients an increase of JAK2 clone correlated with CR whereas no variation of VAFs was associated with absence of CR. CONCLUSIONS In conclusion, we confirmed the poor prognosis of post MPN AML. Classical AML prognostic factors were not validated in our cohort. We identified the presence of mutations other than JAK2/MPL/CALR as the main prognostic factor whereas post-PV AML appeared to do better than post-ET and post-PMF AML. The very poor result of IC with or without ASCT highlights the need to develop specific clinical trials in this subgroup of AML. Disclosures Kuykendall: Celgene: Honoraria; Janssen: Consultancy. Sallman:Celgene: Research Funding, Speakers Bureau. Cluzeau:CELGENE: Consultancy; MENARINI: Consultancy; JAZZ PHARMA: Consultancy.

<p>Blood smear and bone marrow aspiration of patient referred for cytopenia post PARPi.</p>